It is known to replace diseased or damaged articulating surfaces of a joint with prosthetic components in total or partial joint replacement procedures. During such procedures, it is necessary to balance the tension in the soft tissue structures that support the joint, for example the ligaments and surrounding tissues. In certain cases, it is also desirable to correct for deformities. These deformities may be from a pre-existing injury or condition, or may have developed in the joint in parallel with, and usually as a consequence of, the degradation of the natural articulating surfaces. For example, it is common for an ankle requiring total joint replacement surgery to exhibit a certain degree of varus or valgus deformity. This is where the distal bone of the joint is angled either medially (varus) or laterally (valgus) with respect to the normal joint line. Such deformities can be corrected by placing the joint in the desired anatomical alignment before resecting the distal bone articulating surface in preparation for implantation of the prosthetic component. The bone surface will have worn away, or subsided as a result of trauma, to a greater degree in one compartment or the other (depending on the nature of the deformity). Placing the joint in correct alignment before resecting will therefore cause the removal of a non symmetrical piece of bone, removing less bone from the side that is worn away or subsided in order to restore normal alignment to the joint. In conventional surgical procedures, the joint is placed and held in alignment prior to a distal bone resection by a surgical assistant. The correction for varus or valgus deformities is therefore conducted by eye and the accuracy and repeatability of the resection is dependent upon the surgical assistant holding the limb steady in the correct place.